On today’s dairies, capitalizing on herd health and productivity begins well before a first-calf heifer steps foot into the milking parlor. In the 120-day time span a dairy heifer spends on a calf ranch, the immune systems of young heifers are built from square one. The quality of care and extent of any disease exposure during this stage can affect lifelong productivity.
Threats to calf health vary by age. In very young calves, diarrhea is the biggest health threat. But post-weaning, pneumonia becomes the biggest threat to heifer calves. By implementing straightforward management practices, heifers can be healthy and develop into strong breeding-age animals with thrifty immune systems.
Keys to Success: Nutrition
“The viruses these heifers are exposed to set the bacteria up to thrive,” says Dr. Mark van der List, Professional Services Veterinarian with Boehringer Ingelheim Vetmedica, Inc. “Viruses damage the lining of the respiratory tract, and that gives bacteria a greater opportunity to cause disease.”
The first requirement for minimizing respiratory disease on calf ranches is good nutrition. To have well-developed and strong immune systems, heifers must be on a sound diet, according to Dr. van der List. Sometimes, calves in hutches can be underfed, leaving them vulnerable to infection and disease that may have otherwise been avoided. By ensuring these animals are fed properly, a ranch manager is ensuring young heifers develop a strong immune system to combat common pathogens.
Keys to Success: Comfort
Animal comfort plays an important role in minimizing disease risk. Housing environments that are either too hot or too cold put stress on an animal, which in turn may suppress immune system development. Animal housing is also important in preventing nose-to-nose contact between a sick animal and a healthy animal. Much like young children who quickly and easily share a cold virus in a day care center, calves that contact each other can pass a virus among a commingled group rapidly.
Even ranch workers can spread disease. When a worker has handled a sick animal, he should be aware that his hands, clothing and footwear are potentially contaminated, and he should take appropriate steps to sanitize before contacting any other animals on the ranch. Simple husbandry techniques like good nutrition, basic hygiene and comfortable, clean calf housing go a long way in keeping animals healthy.
Keys to Success: Vaccination
Dr. van der List stresses the importance of developing and implementing a comprehensive vaccine protocol to help prevent the viral diseases like BVD, BRSV and IBR that can pave the way for bacterial respiratory pathogens, such as Mannheimia haemolytica, which can affect the productivity of the cow for her entire life.